QES Labs HPBA-2 User manual

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HPBA-2
Balanced Headphone Amplifier
Rev. 6
Owner’s Manual

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1. INSTALLATION
Check that the unit is OFF. Connect power mains cable to an earthed receptacle, connect
the headphones connectors, and the audio cables in the line in connectors on the rear
panel. Check that each connector from cables is firmly inserted into the one on front or
rear panel.
2. CONTROLS
The volume is controlled by the Input Attenuator, a 24-step rotary switch. ou should set it
for comfortable listening level.
3. INPUTS
We suggest that the input level coming from your DAC’s balanced outputs to be adjusted
for 0dBFS = +24dBu (12.28 Vrms).
XLR input connector pin-out is:
PIN 1: Ground
PIN 2: Hot
PIN 3: Cold
Line In connectors are located on the rear panel. Left and Right channels are as follows:
4. OUTPUTS
The front panel XLR headphone balanced connector pin-out is as follows:
PIN 1: Screen
PIN 2: Hot
PIN 3: Cold
Connect a balanced cable to your headphone’s voice coils, so that the voice coil’s positive
terminal is connected to xlr pin 2, and negative to pin 3.

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5. METERS
The VU meters are analog type, and show actual output level on a 300Ω load.
When the needle is on the 0VU indication, there’s a 1 milliwatt signal going through your
headphones (0.548 Vrms).
6. SPECIFICATIONS
Frequency response, 300Ω load, both channels active:
1.5 z – 150k z (+0/-0.5dB)
Input impedance: 20 kΩ
Output impedance: 164 Ω
Total Harmonic Distortion +Noise (THD+N), 300Ω load, both channels active, 1mW output:
0.0026%
C.M.R.R.: > 80dB
Dynamic range: > 120dB

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7. WARRANTY
QES Labs warrants this product against defects in material or workmanship for a period of
two years from the date of original purchase.
QES Labs will repair or replace the defective product at its option if returned within the
warranty period to our designated service facility.
This warranty is in lieu of all other warranties, expressed or implied, including, but not
limited to, any implied warranty of merchantability or fitness for a particular purpose.
8. DECLARATION OF CONFORMITY
I declare that the model “HPBA-2” conforms to the following standards adopted by the
European Community:
EMC (electro magnetic compatibility) 89/336/CEE directive
LV (low voltage equipment) 73/23/CEE directive
on electrical safety (EN61010) and electromagnetic compatibility (EN61000).
RoHS (Restriction of Hazardous Substances) 2002/95/CEE directive.
QES Labs
di Valerio Riccelli
4 Via Ugo Niutta
Napoli, NA 80128
Italy.
Data / Date / Datum: 11/09/2009.
Firma / Signature / Signatur / Unterschrift
Direttore tecnico / Technical manager / Directeur technique.